Plastic in an old house.

[Robbbo]

Hello, this is a frequently asked question, but I didn't find a satisfactory answer...
Someone should really create a FAQ on this subject.

I'm renovating my upper floor with some new walls and electrical work, as well as adding insulation to the exterior walls.

The house was built in 1930, so it has a log structure and metal cladding with insulation added in the 1980s.
On the upper floor, there's just a board and then the log wall.

The plan is to frame it out with 45mm, insulate with a 45mm, hide the electrical wires, and then add PLASTIC?, followed by drywall. Does that sound good?

Best regards, Robert

 

[fridhem]

in a log house, avoid plastic since logs both "absorb" and release moisture. Use 45mm battens and then attach gypsum, but avoid plastic. However, ensure there is negative pressure in the house.

 

[Robbbo]

Oh, so you believe that... and it's just using regular insulation roll and rolling it out on exterior walls and roof then? without plastic...

 

[Robbbo]

everyone agrees with fridhem?

 

[snickarboden]

Hopefully.
Moreover, a differential lock should be tight, and achieving that in an old house is not the easiest.

Yes, a FAQ would probably be needed, there are quite a few questions about this.

/Kent

 

[AndersS]

From what I have managed to learn based on theories and existing experience, you should start with the basic construction of the house during renovation. In your case, I wouldn't have added any plastic. Plastic covering or diffusion barriers work when the entire house is built using this method and with an adapted mechanical ventilation/airflow. In the walls, I would use panels instead of rolled insulation. 45mm is thin, and if you roll out entire lengths, they have trouble staying in place before you get the panels on.

 

[GzO]

No plastic! What would worry me is the insulation from the 80s and the sheet metal facade. Is it sufficiently ventilated?

Regards: Jonas, who is currently sorting out insulations from the happy diffusion-tight 70s

 

[Kurtivan]

Just a thought...., maybe förhydringspapp?

 

[Robbbo]

No plastic! What would worry me is the insulation from the '80s and the metal facade. Is it sufficiently ventilated?

Regards: Jonas, who is currently organizing insulations from the cheerful diffusion-tight '70s

I see replies have come in here... yes, everyone seems to agree on no plastic in my house at least... but there are a few uncertainties... but but I'm going without.

Regarding the insulation under the metal facade, there is a nice gap between the insulation/metal since it is corrugated metal, so it should breathe reasonably well. There seems to be some kind of brown paper on the insulation; maybe it's some type of windproof paper?

Anyway, off I go to continue cutting the old electrical wiring on the upper floor...

 

[Mats]

A FAQ would undoubtedly be a good idea. Anyone interested in starting to write one?